In stereoscopic 3-D display systems, 3-D effect is achieved by presenting slightly different perspectives to each left & right-eye, offset by the distance between the pupils. In frame-sequential implementation of stereoscopic 3-D display systems, image frames for left and right-eye perspectives are not displayed to a viewer simultaneously. Rather, image frames from left and right-eye perspectives may be time sequentially, alternatively displayed. For example, a left-eye frame may be followed by a right-eye frame, which in turn may be followed by a subsequent left-eye frame, which in turn is followed by a subsequent right-eye frame, and so on. To perceive 3D effects from the sequential playing of image frames of different perspectives, the viewer is typically required to wear shuttered glasses (otherwise known as “active” 3-D glasses). Moreover, the shuttered glasses are synchronized with the playing of image frames to ensure that each eye only “sees” one perspective. When a left-eye frame is displayed, the shuttered glasses only open the left-eye, blocking the right-eye; when a right-eye frame is displayed, the shuttered glasses only open the right-eye, blocking the left-eye. Ideally, through the shuttered glasses, a left-eye frame would be seen by the viewer's left eye only, while a right frame seen by the viewer's right eye only. However, even with the shuttered glasses perfectly synchronized to the playing of image frames on a LCD 3-D display, the viewer typically still sees crosstalk between frames of different perspectives i.e. the viewer may see image data of the right-eye perspective from a previous right image frame when the viewer is supposed to see only a left image frame, or vice versa. This occurs because a frame of a single perspective cannot be instantaneously replaced with a new frame of the opposite perspective with LCD 3-D displays. The effect of this is a degradation of the stereoscopic 3-D effect, which can also result in fatiguing of the viewer, as the perspective perception cues become inconsistent with what one would naturally see.
In some approaches, open/close duty cycles of shuttered glasses may be significantly reduced in order to give the viewer a narrower temporal window during which the viewer may see a frame of a single perspective and thus less potential crosstalk between eyes. Specifically, the temporal window may be synchronized with the playing of frames in a display system in such a manner that, in the narrow temporal window, the viewer only sees the frame of a single perspective such as a left frame or a right frame when the frame of the single perspective has fully replaced a previous frame of a different perspective. However, as the temporal window is narrowed by shortening the opening of the “shutter” for an eye, the user will perceive dimmer images, and most of the backlight is wasted when the viewer is blocked from seeing any frame by the shuttered glasses. This is a real-world trade-off in active glasses 3-D systems between crosstalk vs. brightness. Still, the shuttered glasses must be capable of performing fast and responsive switching within very tight timing requirements, in order to realize a precise synchronization of the operation of the shuttered glasses with the displaying of frames.
The approaches described in this section are approaches that could be pursued, but not necessarily approaches that have been previously conceived or pursued. Therefore, unless otherwise indicated, it should not be assumed that any of the approaches described in this section qualify as prior art merely by virtue of their inclusion in this section. Similarly, issues identified with respect to one or more approaches should not assume to have been recognized in any prior art on the basis of this section, unless otherwise indicated.